Abstract
Many signals that modify plant cell growth and development initiate changes in cytoplasmic Ca(2+). The subsequent movement of Ca(2+) in the cytoplasm is thought to take place via waves of free Ca(2+). These waves may be initiated at defined regions of the cell and movement requires release from a reticulated endoplasmic reticulum and the vacuole. The mechanism of wave propagation is outlined and the possible basis of repetitive reticulum wave formation, Ca(2+) oscillations and capacitative Ca(2+) signalling is discussed. Evidence for the presence of Ca(2+) waves in plant cells is outlined, and from studies on raphides it is suggested that the capabilities for capacitative Ca(2+) signalling are also present. The paper finishes with an outline of the possible interrelation between Ca(2+) waves and organelles and describes the intercellular movement of Ca(2+) waves and the relevance of such information communication to plant development.